1. Field of the Invention
The present invention relates to a light adjusting apparatus.
2. Description of the Related Art
Various types of light adjusting apparatus have hitherto been used. As one of the types of such apparatuses, a plug-in type light adjusting apparatus in which, a single or a plurality of optical elements is displaced mutually in and outside an optical path by an electromagnetic driving source or some other type of driving source, and optical characteristics of incident light which passes through the optical path are changed, is available. In recent years, with an achievement of a high-quality image of a portable equipment having an image pickup function and a small-size image pickup equipment such as a micro video scope, with regard to optical elements such as a lens, an aperture, and an optical filter, an application of a focusing lens, a variable aperture, and a variable special characteristic filter instead of a conventional fixed focusing lens, a fixed aperture stop, and a fixed special characteristic filter has been sought strongly. As the abovementioned light adjusting apparatus to be used in such small-size image pickup equipment, such plug-in type light adjusting apparatus which is suitable for small-sizing has been gathering attention because of its simple structure.
As an example of such plug-in type light adjusting apparatus suitable for small-sizing, a light adjusting apparatus disclosed in Japanese Patent Application Laid-open Publication No. Hei 10-20360 is available. This light adjusting apparatus includes a rotor which is polarized to bipolarity. A diaphragm plate is fixed to the rotor via a shaft. The rotor is inserted through a rotating hole into a coil which has been formed to be ring-shaped, and is fixed to be freely rotatable, by a shaft receiver made of a circular cylindrical shaped protruding portion which is formed in an upper cover and a lower cover.